The present invention relates to fluid level monitors for monitoring the level of fluid in a vessel.
A known method of monitoring fluid levels in a vessel is to perform a time of flight measurement. A transducer emits a pulse of ultrasound from either above or below a fluid level and the reflection of the ultrasound from the fluid surface is detected by the transducer, and the time taken for the ultrasound to travel from the transducer to the fluid surface and back is measured. Using the knowledge of the velocity of the ultrasound in the fluid it is possible to then calculate the fluid level.
A further method of monitoring fluid levels in a vessel uses a transducer to emit a pulse of ultrasound in a plane perpendicular to the axis of the vessel and the reflection of the ultrasound from the opposite wall of the vessel is detected by the transducer and the magnitude of the reflected ultrasound is measured.
Both these methods require the fluid to be able to allow the passage of ultrasound therethrough.